Roller blinds are commonly mounted on windows for both residential and commercial applications. Roller blinds are typically fitted with a bottom bar that generally extends across the width of the blind material in order to both present a finished and pleasing termination of the end of the blind material, and to also provide added weight to help the material hang in a relatively taut configuration. In some instances bottom bars may also serve the added function of providing a structure which can be grasped in order to extend or retract the blind material from its roller.
For esthetic purposes, or on account of the overall width of the window to which a blind is to be secured, the blind may be comprised of two or more individual blinds that are mounted end to end. In such instances it is common for the roller tubes of the adjacent blinds to be connected such that a single drive mechanism can be operated in order to lower or retract both blinds simultaneously. Where two blinds are mounted end to end there is a desire to help ensure that the elevation of the bottom bars on the two adjacent roller blinds is the same so that when the blinds are deployed, or retracted, the two bottom bars will be horizontally aligned. For a variety of reasons, following installation the bottom bars of two (or more) such adjacent blinds are often not horizontally aligned. In those situations the installer is typically required to either adjust the winding of one of the blind fabrics upon the roller tube, or to disassemble one of the bottom bars, adjust the length of fabric and then reassemble the bottom bar upon the fabric to achieve horizontal alignment of the two bottom bars.